Questions, answered

A browser-based platform with four purpose-built labs: Digital Logic, Relay, Electricity, and Analog. They share the DigiSim account and access model, but use domain-specific workspaces and simulation models. Their persistence, sharing, and supported project-file formats can differ.

No installation is required. DigiSim has not published a dated browser and operating-system certification matrix; use a current desktop browser with JavaScript and WebAssembly enabled. A laptop or desktop viewport with a mouse or trackpad generally provides the most practical wiring workspace.

Free is available without a recurring charge. Beyond that: Pro monthly or annual and the Founder one-time offer while it is available. Classroom is available as an annual per-seat subscription for Logic Lab.

Open the lab for your subject, place the source, controls, components, and instruments you need, then connect them in that lab’s workspace. Logic uses pins and digital-state colors; the other labs use the wiring and measurements appropriate to their circuit model.

Not to start building. Logic keeps browser-local circuits, Electricity, Analog and Relay each keep one browser-local draft. Sign in for supported cloud saves, unlisted links, public-gallery publishing, account features, lessons, and purchases. Local work does not follow you to another browser.

A laptop or desktop with a mouse or trackpad provides the broadest editor and file workflow. Tablet and phone behavior varies with viewport, browser, and input method, and DigiSim has not published a complete device-certification matrix. Test the specific lab and workflow before relying on it for a class or assessment.

Yes. Logic provides a curated template library with adders, counters, ALUs, and more. Relay has a production catalog containing 37 curated starter Blueprints and 75 archived lesson-staging circuits, while Electricity has guided experiments. Analog has 8 starter examples in 4 groups, including three guided pilots: RC low-pass, half-wave rectifier, and common-emitter amplifier. A full Analog curriculum is not published.

61 in the Logic Lab: the seven basic gates plus buffers; switches, constants, lamps and seven-segment displays; multiplexers, demultiplexers, encoders and decoders; half and full adders, 4-bit and 8-bit adders, ALUs and comparators; latches, flip-flops, registers and counters; 256×8 RAM and ROM; program counter, instruction register and control unit; and an assembly loader, oscilloscope and pixel screen.

Use 4-bit parts to learn a concept with a readable wire count, and 8-bit parts when you want a design that resembles a real machine. Full CPU parts and the larger 8-bit blocks are Pro components.

It is event-driven and applies authored per-component propagation delays in simulator time. This can expose model-level transition ordering, glitches, races, undefined states, high impedance, and contention. It does not characterize transistor behavior, signal integrity, metastability, or physical-device setup and hold limits.

An editor and pin-level loading device that assembles source, then transfers the compiled bytes into RAM over address, data, and control pins. It supports a compact instruction set including LDA, STA, ADD, and JMP. It is part of Pro, alongside the CPU library.

No. Logic Lab currently uses its built-in component palette; it does not support creating custom component types or packaging a circuit as a reusable block. You can open editable templates and build with the available gates and components.

The seven-segment display has eight separate inputs: a–g and the decimal point. Each HIGH input lights its segment. Use the separate 4-bit Digit Display for hexadecimal values, or a decoder to drive the seven-segment inputs. This is a digital display model, not a physical display characterization.

A 16×16 monochrome display model that reads a 32-byte framebuffer region from a 256×8 RAM in the workspace. It has no wired input pins. It is useful for demonstrating memory-mapped pixel output in CPU projects, rather than a general video subsystem. This is a Pro component.

Press an output pin, drag to an input pin, and release. Connected pins are color-coded by state, including high impedance, so you can read the circuit without probing it.

Check for unconnected or undefined inputs, unintended contention, control-pin states, and incomplete wiring. For sequential circuits, verify that the simulated clock reaches each intended clock input. Use wire-state colors, diagnostics, and the logic oscilloscope to inspect the states resolved by the model.

Drop a clock component and right-click it to set the frequency, then wire its output to anything that needs an edge — flip-flops, registers, counters.

It displays supported digital signals against simulator time, including modeled propagation delay, transition ordering, clock relationships, and sequential-state changes. The free catalog includes a basic scope, while Pro adds the eight-channel scope. Neither is a physical oscilloscope or an analog signal-integrity instrument.

A demo or verified template is the most practical starting point. Identify the selected architecture’s clock, program counter, instruction storage and data RAM, instruction register, control unit, ALU, registers, and buses, then verify each stage independently. The Assembly Program Loader transfers compiled bytes into a wired RAM through address, data, and control pins; it does not program a ROM directly. The CPU library requires Pro.

Check missing wires, switch states, control inputs, and bus contention. Unconnected or released data and control inputs are generally sampled as LOW; a driven unknown state can remain unknown. Clock inputs require a definite transition, so do not treat a floating clock as a valid LOW. Use wire-state colors and the logic oscilloscope, then isolate and test one section at a time.

Yes. The event-driven model schedules component output changes after authored delays, and the logic oscilloscope can display those transitions in simulator time. This supports reasoning about model-level glitches and event ordering, but it does not supply silicon timing parameters or replace static timing analysis and hardware measurement.

Undo and redo are available, but their depth is lab-specific and is not published as one cross-platform number. Use the controls shown in the active lab; keyboard bindings can differ.

Persistence is lab-specific. Logic keeps browser-local circuits, Electricity, Analog and Relay each keep one browser-local draft. If you sign in and use a supported cloud-save feature, that circuit is stored on DigiSim servers. Project-file export exists only where that lab provides it.

Browser storage is finite and can be cleared or evicted. Where cloud save is supported, current limits are 5 saves on Free and 250 on Pro or Founder; a confirmed Classroom entitlement follows the terms shown for that account. Exported files, where supported, use storage you control.

There is no general importer for unrelated simulator formats. Import a project only in a compatible DigiSim lab and version using that lab’s supported format; Logic, Relay and Analog do not all use the same extension.

Use an unlisted link or project file only where that lab supports it. Anyone with an unlisted URL can open it, so share only content you are authorized to disclose. A Classroom owner does not automatically see a student’s circuits.

Logic and Electricity use plan-based unlisted links: Free can keep 2 active for 14 days, while Pro and Founder can keep 50 active for 365 days. Anyone with the URL can view an unlisted circuit. Relay has a separate revocable public-link model; Analog sharing is not currently documented. Links are not real-time co-editing.

Browser-local work stays in the original browser and does not sync. Signed-in cloud saves can be opened elsewhere where that lab supports them, subject to the plan quota. Before changing device or clearing browser data, use an available project export or cloud save and verify that the copy opens.

DigiSim’s guided lesson format. A SimCast builds a circuit in front of you step by step, narrating why each component goes where it does, and gets progressively harder across the series. The free tier includes introductory lessons; Pro opens the complete guided lesson catalog.

Yes. Use public lessons, supported links and embeds, and the published component references. The Docs index currently covers Logic, Relay, and Electricity reference families plus a focused Analog guide; it does not claim a complete Analog component library. Classroom supports Logic Lab assignments, saved-work submissions and text feedback.

The guided material ranges from secondary-level gates and combinational logic through introductory undergraduate sequential logic and computer architecture. More advanced learners may use the labs for conceptual exploration or demonstrations, but DigiSim does not replace HDL verification, static timing analysis, SPICE sign-off, or hardware validation.

Teachers can see their class's submitted work and text feedback. Personal drafts and learning activity outside the class remain private. The first version is limited to Logic Lab with annual seat subscriptions and administrator-invoice access.

Classroom supports text feedback on submitted work. Automatic grading and a general gradebook are outside its scope. The first version supports Logic Lab.

The Logic course follows a dependency-ordered sequence: digital foundations and gates, Boolean algebra, arithmetic and routing, sequential state, registers and counters, memory and buses, then processor and computer organization. Later lessons can rely on concepts established earlier, so the published order is recommended.

Free is ongoing. Pro renews monthly or annually. Founder is a one-time offer only while shown at checkout. Classroom renews annually per seat until canceled; administrator-invoice orders follow their accepted terms.

Free includes useful access in all four labs. Persistence and account tools vary: Logic keeps browser-local circuits, Electricity and Analog keep one local draft, and Relay guest work does not persist. Logic and Electricity support 2 active unlisted links that expire after 14 days. Current limits are shown in the product and pricing page.

Pro unlocks the complete current component catalog and all published guided content in the three published courses. Analog has 8 starter examples, including three guided pilots; a full Analog curriculum is not published. Cloud save, unlisted links, embeds, and exports remain lab-specific; where plan-based unlisted links are supported, Pro allows 50 active links with 365-day expiry. Founder has the same feature access while offered. Classroom terms are confirmed separately.

Canceling stops future renewals and paid access normally continues to the end of the period. Existing browser-local work remains where that lab supports it. After the paid entitlement ends, account and cloud features follow current Free limits; make a supported independent copy before the change where possible.

Available plan changes depend on the current billing controls and the offer shown for your account. Review the effective date and amount before confirming a monthly or annual Pro change; Founder can be purchased only while that one-time offer is shown at checkout.

No. A license belongs to one account and is not transferable. Each student can use Free or claim an eligible academic discount; teachers can purchase Classroom seats for Logic Lab.

Stripe hosts checkout and supports the payment methods shown for your location and order. DigiSim does not store full card numbers or card security codes.

Refunds, statutory cooling-off rights and remedies for faulty or misdescribed digital content or services are set out in the Refund Policy. The general Terms or a normal Pay click do not by themselves waive a statutory right.

DigiSim may be used for coursework, portfolios, and demonstrations within the applicable plan, Terms of Service, third-party rights, and your institution’s rules. A paid plan widens product access but does not replace academic-integrity, attribution, confidentiality, or assessment requirements.

A one-time purchase describes billing, not a promise of perpetual online operation. If a material paid service is discontinued, DigiSim will give reasonable notice where practicable, keep available export tools open where possible and provide any remedy required by law.

Yes. Individual students and educators can receive 50% off Pro and the Founder offer while it is available. The automatic check uses a supported school or university email address on your DigiSim account. You do not need to apply on behalf of an institution. Classroom is a separate institutional offer.

Sign in with a DigiSim account registered to a supported school or university email address and complete email verification when prompted. Choose Pro or the available Founder offer. The checkout checks the account email and applies an eligible discount automatically; no separate application or discount code is needed. Confirm the discount and total before paying.

Gmail and other personal email addresses do not qualify through the automatic school-email check. DigiSim does not currently provide a self-service option to add a separate academic email to an existing account. An eligibility check does not change an existing subscription or refund an earlier payment. Your current account and purchases remain associated with that account.

The current offer supports automatic school-email verification only; student documents are not accepted through a separate application process. If your school does not issue an email address or its domain is not recognized, the automatic discount is unavailable. This is a limitation of the verification method, not a determination of your student status. Check the total before purchasing.

Pro remains a monthly or annual subscription. Review the discount duration and recurring total shown at checkout; for an existing subscription, review the next payment in your billing details. The current email-based process does not require an annual submission of student documents. Founder is a one-time purchase and has no recurring renewal.

A dated browser, operating-system, input, and viewport certification matrix has not been published. Use a current desktop browser with JavaScript and WebAssembly enabled for the broadest editor and file support, and test the required lab workflow before a class, examination, or production demonstration.

Enable hardware acceleration, close the tabs you are not using, and disable extensions that touch canvas rendering. If a large design remains slow, test a smaller portion of the design at a time.

Email support@digisim.io or use the in-app feedback control. Include the steps, lab and browser; if safe and relevant, attach the project file supported by that lab. Do not include passwords, full card details or confidential student information.

Private cloud circuits are protected by account permissions: other ordinary users cannot view them unless you share or publish them. DigiSim uses HTTPS to encrypt data in transit, but cannot guarantee absolute security. Local saving varies by lab, and clearing browser data can erase local work. Cloud save, share links, and gallery publishing store circuit content and related metadata on DigiSim servers. Anyone with a valid unlisted link can view the circuit without signing in; gallery publishing makes the circuit public. Firebase handles sign-in and Stripe handles card payments. Google Analytics loads only after consent. Rejecting analytics does not disable security logs or client error reports. Our Privacy Policy states that DigiSim does not sell personal information and explains data use, providers, and retention; the Cookie Policy explains browser storage and analytics choices.

Use “Forgot password” on the sign-in page. You will get an email with a reset link, and your saved work is untouched by the reset.

DigiSim does not currently guarantee offline operation or recovery after a dropped connection. Loading, signing in, cloud features, sharing, catalogs, and SimCast require a connection. Before disconnecting, save or export through a feature that the selected lab explicitly supports.

Viewing may work on some tablets and phones, but editor usability depends on viewport, browser, and input method. Complex wiring is generally more practical on a laptop or desktop with a mouse or trackpad. No exact mobile-width or device guarantee is published.

Shortcuts are lab-specific. Use the controls and shortcut hints shown in the active lab; do not assume that save, copy, paste, delete, zoom, undo, or redo use the same binding everywhere.